It is prior art to make bags into which medium is filled afterwards. For example, this is known by making ice cube bags where medium in the form of water is filled into bags.
Furthermore, apparatuses by which packings that may be filled with medium in the shape of liquid are formed from two plastic film webs, which are either formed by a folded/U-shaped film or by using two superposed separate films, are known. In these designs, a packing is formed at first, which is subsequently filled with the liquid via a filling opening. Then the filling opening is closed, and the liquid-filled packing is ready for further handling.
Furthermore, there is also so-called form-fill-and-seal machines where a film is drawn over a shaping tube, whereby the film is folded for the formation of a packing tube. This packing tube is closed by a welding, and filling of the packing tube is effected through the shaping tube around which the film is folded. Common to the prior art machines is the application of strong and thick films for providing a sufficiently strong packing.
It is thus commonly known that bags are filled with medium in the form of liquid, while they are on a supporting surface, as the film is inadequate for carrying the weight of the bags.
Particularly in connection with bags that are thermally sealed or welded, a softening and weakening of the material occurs, so that there is less load-bearing ability in the heated and softened material. This puts greater demands on the support of the packing during and after the filling of medium.
Examples of prior art methods are known from e.g. U.S. Pat. No. 4,598,529, U.S. Pat. No. 4,587,810, WO 82/04237 and EP 0 999 131.
Common to the techniques described in these publications is the use of thick plastic films and/or use of complicated equipment for application in the making of medium-filled packings.
From U.S. Pat. No. 4,598,529 is also known a method and an apparatus for forming flexible plastic bags with two sides which are formed by superposed plastic webs and for filling the bag with liquid. The system described includes, however, the formation of a bag. This bag is subsequently provided with a slit at one side for filling liquid by means of a filling nozzle. The slit is subsequently closed by thermal sealing means that welds the to sides together. According to this technique, the packing is thus not formed successively while simultaneously being filled. Moreover, according to this art thermal sealing occurs across the entire width of the plastic webs so that a weakening of the material appears such that the web cannot carry a filled packing. There is no indication of the possibility of placing a liquid-filled packing directly in a sales unit and/or distribution unit.
For many years there has been a wish of providing packings filled by medium, preferably a liquid in the shape of water. Also, is has been desired to be able to make such medium-filled packings in the form of ice cube bags, where ice cubes are formed after freezing.
Furthermore, for many years it has been a wish to be able making ice cubes where the risk of bacterial growth is avoided, as known from traditional ice cube machines where the ice cubes are formed in a freezing compartment.
Moreover, there has also existed a wish for making water containers where the risk of bacterial growth is avoided by distributing water directly from a flexible liquid container. In the prior art containers, air penetrating into the container will cause the introduction of oxygen. Thereby a risk of bacterial growth is present.